施工期跨海桥梁矩形设置基础波流力研究  

Study of Wave-Current Forces Acting on a Rectangular Caisson Directly Mounted on Pre-consolidated Seafloor During Construction for Sea-Crossing Bridge

作　　者：康啊真 张东明 李鑫[1] 吴先斌 祝兵[1,2] KANG Azhen;ZHANG Dongming;LI XIN;WU Xianbin;ZHU Bing(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;State Key Laboratory of Bridge Intelligent and Green Construction,Wuhan 430034,China;School of Architecture and Civil Engineering,Chengdu University,Chengdu 610106,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]桥梁智能与绿色建造全国重点实验室,湖北武汉430034 [3]成都大学建筑与土木工程学院,四川成都610106

出　　处：《世界桥梁》2024年第1期79-86,共8页World Bridges

基　　金：国家自然科学基金面上项目(52178167);四川省科技厅应用基础面上项目(2021YJ0039);西南交通大学交叉创新团队项目(YH1500112432297)。

摘　　要：为给跨海桥梁矩形设置基础施工提供参考,研究跨海桥梁矩形设置基础定位下沉过程中墩位水深及结构吃水深度对其波流力的影响。基于垂向多层σ坐标变换模型和大涡模拟LES方法建立三维波浪-流与结构物相互作用的数值仿真模型,分析不同水深及结构吃水深度时,单独波浪作用和波流共同作用下矩形设置基础的波流力及其统计值和流场分布特征,并提出施工期矩形设置基础下沉过程波流力简化算法。结果表明:矩形设置基础在定位下沉过程中,垂直来流传播方向的结构阻水面积随之增大,流场的复杂绕射作用使得波流力峰值呈非线性增大趋势;由于浅水波在整个水深范围影响都比较大,矩形设置基础波流力对结构吃水深度的变化相对深水条件更为敏感;结构波流力峰值不对称系数随吃水深度增加逐渐减小,且波流力表现为正向峰值大于负向峰值的强烈不对称性特点;随着结构吃水深度增加,单独波浪作用、波流共同作用时,在流场复杂绕射作用下,矩形设置基础迎浪侧的波面爬高增大,涡脱现象愈加明显;提出的跨海桥梁矩形设置基础下沉着床过程波流力简化算法可用于估算设置基础施工期波流力。This paper studies the influence of water depth at pier site and structural draught depth on the wave-current forces acting on sea-crossing bridges,during the positioning and sinking of the rectangular caisson that will be directly mounted on the pre-consolidated seafloor.The interaction between three-dimensional wave-current and structure was numerically simulated based on the vertical multi-layerσ-coordinate transformation model and large eddy simulation method(LES).The wave-current forces on the rectangular caisson,the statistics and flow field distribution characteristics under the action of pure waves and wave-current interaction were analyzed,considering the fluctuation of water and structural draught depths,and a simplified method to calculate the wave-current forces during the settling process of the rectangular caisson was presented.As per the analysis,for the rectangular caisson that will be seated on the pre-consolidated seafloor,the water resistance area of the structure in the vertical direction of the upcoming flow increases during the sinking process,and the peak wave(current)force shows sign of a nonlinear increase due to the complex diffraction effect of flow field.The shallow water waves are quite powerful in the overall deep water area,which makes the wave-current forces imposed on rectangular caisson more sensitive to the structural draught depths rather than the water depths.As the structural draught depth increases,the asymmetry coefficient of the peak wave(current)forces on the structure dwindles,while the wave-current forces exhibiting a strong asymmetry characteristic where the positive peak overtakes the negative peak.The increase of structural draught depth results in the rise of the wave run-up on the waveward side of the rectangular caisson as well as more notable vortex-shedding phenomenon.The presented simplified method can effectively calculate the wave-current forces imposed on the rectangular caisson settling to the pre-consolidated seafloor.

关 键 词：跨海桥梁 矩形设置基础 墩位水深 吃水深度 波浪力 波流力 数值模拟 

分 类 号：U443.1[建筑科学—桥梁与隧道工程] U441.2[交通运输工程—道路与铁道工程]